Thanks for looking at this.
On our 2.7, we can not submit any assignment. The message that is displayed is 'Submissions closed' even though due dates are not enabled. Any help is really appreciated.
Thank you Ben.
Justin Hunt (POODLL Guy) was able to solve the issue. Apparently in 2.7, one needs to be enrolled in a course in order to submit an assignment. My admins were pretty stressed because they wanted to check that the submit assignment was working, but it was not for them and there was no obvious error message. Once they enrolled in the course, they could submit. Good to know.
I just saw this same problem experienced in the French forums and was reminded of this thread -so thanks again to Justin, (and to Dirk for having the problem ) I have added it to the Assignment FAQ - I see "Submissions closed" even though the submission and cut-off dates are in the future.